The areas of investigation: 1. Cytogenetic studies of human neoplastic, hematological, and congenital disease, with special emphasis on patients with aquired immune deficiency syndrome (AIDS) who develop leukemia, lymphoma, or Kaposi's sarcoma, and patients with adult T-cell lymphoma and leukemia. 2. In situ hybridization studies: a. Localization of c-oncongenes (c-myc, c-sis, c-fms, etc.) in the neoplastic cells (direct or tissue culture) of Burkitt's lymphoma (including /AIDS), CML, Ewing's sarcoma, 5q-syndrome, etc. b. Localization of pseudogenes c-Ki-ras-i and c-Ha-ras-Z in normal human lymphocytes. c. Localization of HTLV gene in patients with HTLV positive diseases; one patient with HTLV leukemia has been studied thus far. d. Localization of the genes for DHFR in various HSR and double minute bearing tissues culture lines.